Rotary face seal assembly

ABSTRACT

A face seal assembly for cooperation with a mating ring to provide a rotary face seal, the assembly including a stressed resilient sealing ring which provides a secondary seal and, in addition, cooperates with other structure for maintaining the parts in assembled relation during storage and handling. The assembly also includes a pair of secured anti-rotation members for a seal nose member each having a retaining tab serving to hold in the assembly the anti-rotation member in the event it becomes unsecured. A biasing annular wave spring of generous size permits yieldable axial movement of the nose member. The aforesaid secured anti-rotation members are received in diametrically opposed peripheral slots in both the nose member and biasing spring, the respective slots in the nose member and spring being aligned, the retaining tabs of the anti-rotation members lying on the side of the spring opposite the nose member. The slots in the wave spring are located midway between adjacent peaks and valleys of the spring so the retaining tabs which are aligned therewith serve as rigid stops preventing permanent deformation of the spring due to axial thrust of the nose member. The design of the parts of the assembly is such that the structural features responsible for the various functions are accommodated for the most part within an axial length of the nose member which has uniform cross-sectional size and shape, thereby providing a nose member of desirable size possessing high structural integrity.

nited States Patent [191 Voitik ROTARY FACE SEAL ASSEMBLY [75] Inventor: Robert M. Voitik, Glenview, Ill. [73] Assignee: Innovatex Corporation, Glenview,

' Ill.

22 Filed: June 20, 1972 [21] Appl. No.: 264,446

[52] US. Cl 277/40, 277/85 [51] Int. Cl. Fl6j 15/40, F16j 15/54 [58] Field of Search 277/38, 39, 40, 41, 277/81, 84, 85, 88

[56] References Cited UNITED STATES PATENTS 3,013,823 12/1961 Schulz 277/40 3,552,752 1/1971 Lojkutz 277/40 3,689,083 9/1972 Greenawalt 277/40 FOREIGN PATENTS OR APPLICATIONS 946,534 l/l964 Great Britain 277/40 Primary ExamirierWilliam T. Dixson, Jr. Assistant Examine! :LKQhfiFU- Smith] Att0rneyCurtis F. Prangley et al.

[57] ABSTRACT A face seal assembly for cooperation with a mating ring to provide a rotary face seal, the assembly including a stressed resilient sealing ring which provides a secondary seal and, in addition, cooperates with other structure for maintaining the parts in assembled relation during storage and handling. The assembly also includes a pair of secured anti-rotation members for a seal nose member each having a retaining tab serving to hold in the assembly the anti-rotation member in the event it becomes unsecured. A biasing annular wave spring of generous size permits yieldable axial movement of the nose member. The aforesaid secured anti-rotation members are received in diametrically opposed peripheral slots in both the nose member and biasing spring, the respective slots in the nose member and spring being aligned, the retaining tabs of the antirotation members lying on the side of the spring opposite the nose member. The slots in the wave spring are located midway between adjacent peaks and valleys of the spring so the retaining tabs which are aligned therewith serve as rigid stops preventing permanent deformation of the spring due to axial thrust of the nose member. The design of the parts of the assembly is such that the structural features responsible for the various functions are accommodated for the most part within an axial length of the nose member which has uniform cross-sectional size and shape, thereby providing a nose member of desirable size possessing high structural integrity.

10 Claims, 9 Drawing Figures PATENTEUJAH 4 3.784.213

SHEET 1 OF 2 FIG.3

BACKGROUND OF THE INVENTION This invention relates to rotary face seals, and more particularly to an improved face seal assembly which cooperates with a mating ring to provide a rotary face seal for use between a housing and a rotatable-shaft.

The closest prior art known to applicant is his own US. Pat. No. 3,245,692, dated Apr. 12, I966. The counterpart face seal assembly shown inthe prior patent, while an improvement over predecessor assemblies, presents certain problems.

For example, the parts ofthe face seal assembly of the patent are held in assembled relation for storage and handling by means of deforming one or more metallic members, meaning that assembly, disassembly and reassembly involve successive bending operations likely to produce structural weakness and premature failure.

Further, anchor member 40 in the patent (FIGS. 1 and 2) which keeps stator 20 from rotating is secured to outer wall 24, and in the event member 40 becomes unsecured, is subject to dropping out of the assembly or other difficulty.

Biasing wave spring 35 which permits axial movement of stator 20 is subject to permanent deformation, thereby rendering the spring ineffective and permitting leakage between relatively rotating'parts l5 and 20.

In addition, the arrangement of parts in the seal assembly of the patent is such that stator has comparatively short axial length in relation to the axial length of the assembly and comparatively low structural integrity.

The aforesaid problems with the face seal assembly of the aforesaid patent are overcome in the present development, as will be seen.

SUMMARY OF THE INVENTION The invention contemplates a face seal assembly for a rotary face seal wherein the respective parts are retained in assembled relation for-handling and storage without bending or deforming any metal part, and are assembled, disassembled and reassembled by simple snap-in and snap-out procedure. The retention mechanism of' the snap-in and snap-out procedure involves stresses exerted by a deformed resilient sealing ring and friction encountered in relative movement of a part with respect to the deformed ring. Thus, repeated assembly and disassembly does not cause a weakening of any part.

The invention also contemplates secured antirotation members effective to prevent rotation of the seal nose member, the anti-rotation members each having an integral tab located in the assembly such that should the anti rotation member become unsecured, the member is restrained from working its way out of the assembly or causing other difficulty.

The aforesaid integral tab, in addition to its retaining function, also performs the function of preventing permanent deformation of the biasing wave spring which permits axial movement of the nose member. The wave spring is oriented with respect to the retaining tabs so the latter constitute rigid stops which prevent objectionable permanent deformation.

The face seal assembly of the invention is so designed that the seal nose member is relatively large in size compared with the size of the assembly, and the structural features responsible for the improved functions of the assembly are accommodated for the most part within an axial length of the nose member which has generally uniform cross-sectional size and shape, providing a nose member possessing comparatively high structural integrity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view through onehalf of an annular rotary face seal assembly embodying the invention, the assembly mounted on a housing wall in effective relation with a cooperating mating ring on embodying the invention.

FIG. '5 is a side elevational view of an anti-rotation member used in the assembly.

FIG. 6 is an end elevational view of the anti-rotation member shown in FIG. 4.

FIG. 7 is a perspective view of the anti-rotation member shown in FIGS. 4 and 5.

FIG. 8 is a fragmentary front elevational view of a seal nose member for the assembly showing one of the two diametrically opposed longitudinal anti-rotation slots therein.

FIG. 9 is a fragmentary front elevational view of a biasing wave spring showing one of the two diametrically opposed slots therein to receivean anti-rotation member, the slot being located midway between a wave peak and an adjacent wave valley of the spring.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, a rotary face seal assembly 10 embodying the invention is shown in effective relation with a rotatable shaft 11 having a mating ring 13 and sleeve secured thereon, the assembly shown mounted in a housing wall 14. It will be understood that assembly 10 is annular in shape, and that FIG. 1 is a longitudinal sectional view through one-half of the assembly.

Assembly 10 includes an annular cup 15 having an outer cylindrical wall 16 and an inner cylindrical wall 17, the two walls being connected at one end by an annular end wall 18.

One of the cylindrical outer and inner walls 16 and 17, for example inner wall 17 as shown in FIG. I, has an annular recess 20 spaced from end wall 18 and opening toward the other cylindrical wall, in this instance toward outer wall 16. The purpose of recess 20 will be described later.

FIG. 4 shows a modified rotary face seal assembly wherein outer cylindrical wall 16' of annular cup 15' has annular recess 20' spaced from end wall 18' and opening toward inner wall 16'. This arrangement generally is an inversion or reversal of the comparable structure shown in FIG. 1. Reference numerals primed are used in FIG. 4 to designate cooperating structure (described above, or following) corresponding to structure in FIG. 1 designated by the same numerals.

Digressing briefly, it will be understood that the assembly corresponding to applicants assembly or 10', while perhaps normally mounted in a housing wall to constitute the stator component ofa rotary face seal, alternatively can be mounted on the rotating shaft and thus constitute the rotor component. When mounted as a rotor, the cooperating mating ring would be the stator component of the seal. Applieants assembly 10 thus is subject to use either as a stator component or a rotor component of a rotary face seal.

Referring again to FIG. 1, recess in inner cylindrical wall 17 is defined in part by an annular shoulder 21 on the left and an annular lip 22 of lesser radial dimension on the right. However, the radial dimension of lip 22 is subject to variation. A second annular lip 23 may be provided on inner wall 17 in general alignment with shoulder 21, the lip providing a slight clearance with part of an annular seal nose member which next will be described.

An annular seal nose member 25 of suitable material such as a carbon composition is disposed for the most part between outer and inner cylindrical walls 16 and 17. A portion 26 of nose member 25 projects beyond the free ends of walls 16 and 17, terminating in an annular plane face 27 adapted to engage mating ring 13 in sealing manner. Projecting portion 26 and an adjacent portion of annular nose member 25 have a reduced inner diameter, defining a cylindrical wall 28 disposed in close association with lip 22 of cylindrical wall 17.

Seal nose member 25 has a pair of diametrically opposed longitudinal anti-rotation slots 30 in the cylindrical surface thereof remote from annular recess 20 in cup wall 17, one of which is shown in FIGS. 1 and 7. The other slot 30, of course, is diametrically opposite. The purpose of the longitudinal anti-rotation slots 30 will be described later, although, as will be seen, they cooperate to prevent relative rotation between cup 15 and nose member 25.

The end region of nose member 25 opposite projecting portion 26, in the form shown in FIG. 1, has an annular lip 32 extending radially inwardly, the dimension of lip 32 such that slight clearance exists with lip 23 of wall 17 so nose member 25 may be assembled and disassembled with respect to cup 15. The purpose of lip 32 will be described later, but it can be said now that lip 32 is optional, and that nose member 25 is subject to modification with respect to structure which substantially performs the function of lip 32.

A layer of anti-friction material'such as low friction plastic material, diagrammatically indicated by heavy line 35, is provided on the cylindrical surface of nose member 25 generally opposite recess 20 or 20' in one or the other of the cup walls 16 and 17. In the FIG. 1 assembly, the layer of anti-friction material covers the inner cylindrical surface of nose member 25 to the right of lip 32.

FIGS. 2 and 3 show modifications in nose members 25a and 25b which perform the function of previously mentioned annular lip 32. Thus, in FIG. 2, heavy line 35a designates a layer of anti-friction material which terminates short of the Iefthand end of nose member 25a. The left end region 36 adjacent anti-friction material 35a is a region possessing relatively higher friction, this high friction region cooperating, as will be seen, to perform the function of lip 32.

The modified nose member 25b shown in FIG. 3 has a layer of anti-friction material designated by heavy line 35b which terminates short of the left end region. An inwardly extending radial lip 32b, comparable to lip 32 in FIG. 1, is provided at the lefthand end of nose member 25b, and an annular recess 37 is provided between anti-friction layer 35b and lip 32b. As will be seen, the lip and recess shown in FIG. 3, or recess 37 alone, cooperate to perform the function of lip 32 in FIG. 1 and the higher friction region 36 in FIG. 2.

Referring again to FIG. 1, a resilient sealing ring 40 is disposed within annular recess 20 and squeezed between the recess bottom and seal nose member 25 to provide a secondary seal. It will be understood, of course, that sealing ring 40 would engage the exterior cylindrical surface of nose member 25 in the event recess 20 were located in outer cup wall 16.

In addition to providing a secondary seal, sealing ring 40 cooperates with recess 20 and nose member 25 to resist disassembly of the latter during storage and handling. The lip 32 of nose member 25 in FIG. 1, the higher friction region 36 of nose member 25a in FIG. 2, the recess 37 of nose member 25b of FIG. 3, with or without lip 32b, each cooperate with the stressed sealing ring 40 to resist disassembly of nose member 25 from cup 15 during storage and handling. These various structural features which resist disassembly contribute greatly to the advantages possessed by the face seal assembly of the invention.

Seal nose member 25 and modified members 250 and 2512 which engage relatively rotating mating ring 13 to perform the face sealing function are restrained from rotating within cup 15 by means of anti-rotation members which are best shown in FIGS. 4-6. Two such members 45 are used in the illustrated seal assembly, located respectively in the diametrically opposed longitudinal anti-rotation slots 30 in nose member 25.

Referring to FIGS. 4-6, the illustrated anti-rotation member 45 is channel shaped in transverse cross section, having legs 46 and 47 and a connecting web 48. At one end of member 45, legs 46 and 47 terminate short of the end of web 48, and the projecting end of the web is bent at right angles to provide a retaining tab 50. As will be seen, when a rotation member 45 is mounted in assembly 10, tab 50 extends radially in the assembly.

Anti-rotation members 45 are secured to a cup wall in diametric relation with each other, and in the form of the invention shown in FIG. 1 are secured to the inner cylindrical surface of outer cup wall 16. As shown in FIG. 1, retaining tab 50 lies against annular cup end wall 18 and extends radially over the major radial dimension of the wall. A member 45 is suitably secured to cup 15 as by spot welds diagrammatically indicated by 51, 51. As previously mentioned, anti-rotation members 45 are received within anti-rotation slots 30 in nose member 25 when the latter is in assembled position.

Limited axial movement of nose member 25 relative to cup 15 is provided resiliently by means of a biasing spring positioned between cup end wall 18 and nose member 25. As shown in FIGS. 1 and 8, biasing spring 55 is an annular wave spring which, like nose member 25, has a pair of diametrically opposed peripheral slots 56 which receive anti-rotation members 45.

Slots 56 in biasing wave spring 55 each are located midway between a wave peak and an adjacent wave valley where the bending stress in the spring is substantially zero. Retaining tabs 50 of the anti-rotation members 45 back up spring 55 in radial alignment with slots 56 and provide rigid stops which prevent permanent deformation of the spring due to axial thrust of the nose member 25, thereby giving tabs 50 an important secondary function.

The primary function of the dual purpose retaining tab 50, of course, is to hold captive the anti-rotation member 45 in the event the member becomes unsecured from cup 15. Absent the retaining tab 50, an unsecured member 45 would be subject to objectionable disassembly or other difficulty during operation of the face seal.

In addition to the improved structural and functional features of the face seal assembly described previously, the shape and organization of the component parts provide a face seal assembly wherein the several functions are achieved within a restricted axial dimension, thereby minimizing axial length of the assembly without sacrifice in the size and structural integrity of nose member 25. Thus, as will be seen, nose member 25 has a major intermediate length of uniform cross-sectional size and shape between its end regions, thereby avoiding points of structural weakness in the major intermediate length. Anti-rotation slots 30, for the most part, and the region engaged by resilient sealing ring 40 providing the secondary seal both fall within the axial length of member 25 possessing uniform crosssectional shape and size.

From the above description it is thought that the construction and advantages of this invention will be readily apparent to those skilled in the art. Various changes in detail may be made without departing from the spirit or losing the advantages of the invention.

Having thus described the invention, what is claimed as new and desired to secure :by Letters Patent is:

l. A rotary face seal assembly, comprising:

an annular cup having spaced outer and inner cylindrical walls and an annular end wall therebetween, one of said walls having an annular recess spaced from said end wall and opening toward the other of said walls;

an annular seal nose member between said inner and outer cup walls and projecting beyond the free ends thereof, said seal nosemember having a pair of diametrically opposed longitudinal anti-rotation slots in the cylindrical surface thereof remote from said annular recess;

a resilient sealing ring within said annular recess of said one of said cup walls squeezed between the re cess bottom and said seal nose member, providingtion of a layer of anti-friction material on the cylindrical surface of said annular seal nose member in the region engaged by said sealing ring, whereby said seal nose member may move axially without excessive friction.

3. The rotary seal assembly of claim 2 wherein said layer of anti-friction material has spaced relation with the end of said seal nose member adjacent said cup end wall, cooperating with said sealing ring to provide an end region of relatively high friction to resist disassembly of said seal nose member during storage and handling. l

4. The rotary seal assembly 'of claim 1 wherein the end of said annular seal nose member adjacent said cup end wall has a radial annular projection of small dimension, providing interference with said sealing ring to resist disassembly of said seal nose member during storage and handling.

5. The rotary seal assembly of claim 1 wherein a cylindrical surface in the end region of said annular seal nose member adjacent said cup end wall has an annular recess which on relative axial movement between said cup and said seal nose member receives said sealing ring to thereby resist disassembly of said seal nose member during storage and handling.

6. The rotary seal assembly of claim 1 wherein the end of said annular seal nose member adjacent said cup end wall has a radial annular projection of small dimension and an annular recess between said projection and said sealing ring, said projection and recess both cooperating with said sealing ring to resist disassembly of said seal nose member during storage and handling.

7. The rotary seal assembly of claim 1 wherein each anti-rotation member is a channel having parallel side walls and a connecting web, said web secured to said cup wall and having an unsecured extension bent radially of said cup wall to provide said retaining tab.

8. The rotary seal assembly of claim 1 wherein said biasing spring is an annular wave spring, said wave spring having a pair of opposed slots to receive said anti-rotation members, the retaining tabs of said antirotation members disposed between said cup end wall and said wave spring.

9. The rotary seal assembly of claim 8 wherein said slots in said wave spring are each located midway between a wave peak and adjacent wave valley where the .bending stress at said slots is substantially zero,

whereby saidretaining tabs form a rigid stop preventing permanent deformation of said wave spring due to axial thrust of said seal nose member.

10. In a rotary face seal assembly, an annular seal nose member of uniform cross-sectional size and shape between the end lengths thereof, said member having a pair of diametrically opposed longitudinal antirotation slots in one cylindrical surface, the other cylindrical surface within the axial length of said slots adapted to be engaged by a resilient sealing ring to provide a secondary seal, whereby said seal nose member possesses high structural integrity and has anti-rotation slots and a secondary sealing surface within an axial length no greater than that required for said antirotation slots. 

1. A rotary face seal assembly, comprising: an annular cup having spaced outer and inner cylindrical walls and an annular end wall therebetween, one of said walls having an annular recess spaced from said end wall and opening toward the other of said walls; an annular seal nose member between said inner and outer cup walls and projecting beyond the free ends thereof, said seal nose member having a pair of diametrically opposed longitudinal anti-rotation slots in the cylindrical surface thereof remote from said annular recess; a resilient sealing ring within said annular recess of said one of said cup walls squeezed between the recess bottom and said seal nose member, providing a secondary seal; a biasing spring between said cup end wall and said seal nose member; and a pair of anti-rotation members secured to a cup wall and projecting into the anti-rotation slots of said seal nose member, said members each having a retaining tab lying between said cup end wall and said seal nose member for maintaining said members captive if they become unsecured from said cup wall.
 2. The rotary seal assembly of claim 1 with the addition of a layer of anti-friction material on the cylindrical surface of said annular seal nose member in the region engaged by said sealing ring, whereby said seal nose member may move axially without excessive friction.
 3. The rotary seal assembly of claim 2 wherein said layer of anti-friction material has spaced relation with the end of said seal nose member adjacent said cup end wall, cooperating with said sealing ring to provide an end region of relatively high friction to resist disassembly of said seal nose member during storage and handling.
 4. The rotary seal assembly of claim 1 wherein the end of said annular seal nose member adjacent said cup end wall has a radial annular projection of small dimension, providing interference with said sealing ring to resist disassembly of said seal nose member during storage and handling.
 5. The rotary seal assembly of claim 1 wherein a cylindrical surface in the end region of said annular seal nose member adjacent said cup end wall has an annular recess which on relative axial movement between said cup and said seal nose member receives said sealing ring to thereby resist disassembly of said seal nose member during storage and handling.
 6. The rotary seal assembly of claim 1 wherein the end of said annular seal nose member adjacent said cup end wall has a radial annular projection of small dimension and an annular recess between said projection and said sealing ring, said projection and recess both cooperating with said sealing ring to resist disassembly of said seal nose member during storage and handling.
 7. The rotary seal assembly of claim 1 wherein each anti-rotation member is a channel having paRallel side walls and a connecting web, said web secured to said cup wall and having an unsecured extension bent radially of said cup wall to provide said retaining tab.
 8. The rotary seal assembly of claim 1 wherein said biasing spring is an annular wave spring, said wave spring having a pair of opposed slots to receive said anti-rotation members, the retaining tabs of said anti-rotation members disposed between said cup end wall and said wave spring.
 9. The rotary seal assembly of claim 8 wherein said slots in said wave spring are each located midway between a wave peak and adjacent wave valley where the bending stress at said slots is substantially zero, whereby said retaining tabs form a rigid stop preventing permanent deformation of said wave spring due to axial thrust of said seal nose member.
 10. In a rotary face seal assembly, an annular seal nose member of uniform cross-sectional size and shape between the end lengths thereof, said member having a pair of diametrically opposed longitudinal anti-rotation slots in one cylindrical surface, the other cylindrical surface within the axial length of said slots adapted to be engaged by a resilient sealing ring to provide a secondary seal, whereby said seal nose member possesses high structural integrity and has anti-rotation slots and a secondary sealing surface within an axial length no greater than that required for said anti-rotation slots. 